- BASIC PROBLEM AND OBJECTIVE: According to published reports, the incidence of lymphoedema of the arm in patients with cancer of the breast, treated by either surgery or radiotherapy, varies widely. We obtained basic data on the treatment of breast cancer in a large number of patients in order to determine the relationship between the incidence of lymphoedema and the radical nature of the primary treatment. PATIENTS AND METHODS: Data were collected on all women with lymphoedema of the arm after treatment for breast cancer between 1972 and 1995. The increase in arm circumference was measured by a standardised method. Only those patients were included in the final analysis whose arm circumference had increased by at least 2 cm. The type of operation and(or) radiotherapy, tumor histology and TNM classification were recorded. RESULTS: There were 1405 cases of arm lymphoedema after treatment of 5868 cases of breast cancer (24%). 2515 breast cancers had been treated surgically. 3353 surgically and by radiotherapy. Lymphoedema occurred in 22.3% after radical mastectomy without radiotherapy and in 44.4% with it; after modified radical mastectomy without radiotherapy in 19.1%, in 28.9% with radiotherapy; after breast-preserving operation without radiotherapy in 6.7%, with radiotherapy in 10.1%. Until the 1970s radical mastectomy with conventional postoperative radiotherapy has been the treatment of choice, with 38% cases of lymphoedema. This incidence gradually decreased to 16% in subsequent years. CONCLUSION: The incidence of lymphoedema of the arm depends on the radical nature of the primary treatment. The quality of life could be easily improved through minimising the incidence of lymphoedema if current standards of breast-preserving surgery were generally practised.